Pneumatic tool.



W. SHERWOOD.

PNEUMATIC TOOL.

APPLICATION mw FEB. 2. 1914,

Patented Oct. 19, 19M).

M'Zjj I Wmwhx i MM45/ MM.

UNITED STATES PATENT OFFICE.

MATHER W. SHERWOOD, OF FRANKLIN, PENNSYLVANIA, ASSIGNOR TO CHICAG PNEUMATIC TOOL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW JERSEY.

PNEUMATIC TOOL.

Specification of Letters Patent.

Patented Oct. 19. 7l 9i 5.

Application filed February 2, 1914. Serial No. 816.085.

To all whom it may conce/rn Be it known that I, MATHER lV. SHER- woon, a citizen of the United States, residing at Franklin, in the county of Venangro and State of Pennsylvania, have invented certainhew and useful Improvements in Pneumatic Tools, ot' which the following is a specication.

My invention relates to tool operated by a motive fluid such con'ipressed air and the object thereof is to provide a simple and ellicient construction and new mode of operation of valve mechanism and also to improve the means whereby the same may be arranged and assembled in the tool and be removed therefrom whenever desired.

In the drawings Figure 1 is a central longitndinal section of a. pneumatic tool in the form of a hand drill embodying my invention; Fig. 9. a detail section showing means for fastening or clamping the parts together; Fig. 3 an elevation of the ':yliruler or body of the valve Cage illustrating the preferred form thereof and Fig. 4. a section on the line 4 4 of Fig. 3.

inasmuch as my invention relates to the valve mechanism of'a tool it is evident that the. other parts of such tool may partake of different forms and be of ditl'erent types but for convenience and detiniteness of description and disclosure ot my invention I have chosen to illustrate and Will hercin after describe the same embodied in a pneumatic tool ot the hand-drill type. with` ont intention oi limiting myself thereto.

The pneumatic tool herein shown com prises a main cylinder l, a handle 2 clamped thereto in' the manner hereinafter described, a piston 3 reciprocahle Within the cylinder` a striking piece or anvil 4 age inst which the blows of the piston are transmitted through the medium of the piston stem 3, andthe Working tool which is here in the forni ot a drill bit or steel 5. This tool is of the type having a rotary drill chuck 6 but inasmuch as this feature is immaterial to the present invention the same Will not be described. The cylinder 1 contains a piston chamber 1a having suitable ports and passages for the admission and exhaust of pressure to and from opposite ends including a rear port 7 and a front port 8, the former cmmunicatingA directly 'with a valve chamber 9 formed in the body of the cylinder and the latter indirect-ly therewith through the passage 10.

The piston chamber is also provided with exhaust ports ll and exhaust grooves ll communicating therewith, and also with haust grooves and ports ll. "1

ll'ithin the valve chamber 9 is contained the distributing valve mechanism which con trols the admission ot the live air through l the supply passage 12 to opposite ends et the piston chamber for reciprocatingV the piston. This valve mechanism preierahl. ot the ball type shown, comprises a valve eje which is removably positioned in the 'front enol of the valve chamber and contains a hollow ball 13 acting as a valve. The ball cage, consists of a shell li and the two end pieces l5 and ltieach provided with the central ports 17 and 18 and each acting' a seat with respect. to the hall valve. Each seat provided `with a marginal flange tittiuf; accurately within the valve chamber and extends into the shell. series ci" pr ts lil extend through the shell and connnimicate between the annular space 20 surrounding the valve cage and the interior olif such cage, such annular space of course Kommune cating with the source of motive fluid sup-- ply. ll'hen .the hall valve in its lett hand position shown in Fig'. l the commnnh cation from the, source of supply to the front end of the piston chamber is open. the route being; through the connection l2, annular space 20, interior ot" the valve cage. port l?, passage 10 and port aim passage A the same time, the live motive iiuid ie pn t in the annular space 13"* in the left hand corners ot' the interior of the valve cane and on the lett hand face of the hall, with the rf*- sult hereinafter explained. When the i ll valve is in its riiht hand position the ve motive tluid is admitted iron; the, source et supply through the, connection li, annular space 20, interior of the valve rage, 1port left. hand end of valve chamber l) and nort- 7 to the rear end of the piston chaanber.` ln

this right hand position of the ball, the live motive fluid is present in the annular space ...lt that the piston will be forced to the rear emi 2 i,157',4ao

of the chamber. As soon as the front end of the piston has cleared the exhaust groove l1, the pressure in the front end of the piston chamber and also in the supply passages 8 and l() will be rapidly and. materially decreased., much more rapidly than it can be supplied through the ports 19. Consequently the live motive huid .which is present in the space 13 will exert its pressure against the ball and force the same to the right thereby closing the poi-tl? and opening the port 18. The .live motive iluid will thereupon pass to the rear end of the piston chamber and drive the piston forwardly to deliver its blow upon the anvil l which in turn delivers the blow lo the ,drill bit 5. lVhen the piston in its forward travel uncovers the other exhaust groove l1b the pressure in the rear end of the piston chamber and also in the communicating passages will be rapidly and materially decreased, whereupon the live motive fluid in the space '13h will exert its pressure against the ball and force the latter back to the starting position shown in lfig. 1, thereby completing a full cycle of operation. lt will be understood that the ports lJ are of limited carrying capacity compared with the large ports S and l0 and 17 also the exhaust grooves and passages.

In so far as the feature oi the valve movement in its broader aspect is concerned. the precise shape of the valve proper is immaterial so long as it is such that the movement thereof in the manner described is effected, but I prefer to employ a ball as such valve.

By preference the ports 19 in the valve cage are formed at an angle to the longitudinal axis thereof as shown in Fig. 4 so that the current of incoming motive fluid will have a teiidencyy to properly rotate the valve so that it will ybe constantly changing its position Vith respect to the valve seat in order to avoid any possible wearingI olk the seating surface of the hall in any one. place.

As hereinbeforc stated the valve cage fits into the forward end of the valve chamber. This fit is a loose one` the parts of the cage being assembled and pushed into such end of the valve chamber. ln order to hold the parts ot the valve cage in their assembled condition and with yielding pressure l inter-pose between the valve-seat 16 and the outer end of the valve chamber a coiled spring 2]. By preference l provide at the outer end of the valve chamber a cap closing such end of the chamber and forming' the outer abutment Vt'or the eoiled spring.

The front head 26 is by preference clannaed to the cylinder by suitable bolts such as the side bolts I3 passing through the lug "il oi 'the .:Ivlinder and the lug '2;1 formed on the iront head. rthe iront end of each side bolt cai sies the usual cushion spring 2T and the end nut The handle is by preference bolted to the cylinder by bolts 29 of which only one is showin these bolts passing through the lugs 30 and 31 on the handle and cylinder respectively. In practice the valve mechanism assembled in the position shown in, Fig. .l and in the act of clamping the handle to the cylinder' and back head by means of the side bolts the end cap is forced `and held in place and conseouentlv the parts of the valve mechanism are retained in place through the medium of the coiled spring 2l. lf desired, the end cap could be ma de to screw into the rear end ot' the valve chamber but l prefer the slid ing tit shown in Fig. l which permits of ready assembling and disasscmbling of,y the parts.

I claim:

1. The combination ot' a cylinder having ports and passages for the admissioiy and eX- haust ot motive fluid. a piston reeiprocable in the cylinder, and valve mechanism controlling said ports and passages comprising a valve chamber having oppositely arranged seats provided with ports and a valve arranged to vibrate between such seats and to alternately close the ports in the seats, the valve chamber having a motive fluid supply port of less carrying capacity than the ports in the seat and the exhaust port and passage oi." the cylinder, the valve and its chamber being constructed to provide a space for the motive fluid at each end of the chamber between it and the valve when at such end, whereby the motive liuid in such space n ill force the valve to the opposite end of the valve chamber when such latter end is at exhaust.

if. The combination of a cylinder having ports and passages for the admission and exhaust of motive fluid. ay piston reciprocable in the cylinder` and 'valve mechanism controlling 4said admission ports and passages comprising a valve chamber having oppositely arranged seats provided with ports and a valve arranged to vibrato between such seats and to alternately close the ports in the seats. said valve being a ball and the valve chamber having a motive tluid supply port of less carrying capacity than the ports in the and the exhaust port and passage of the cylinder, the ball valve in each ot its end positions providing a space for the motive fluid between it and the corners of the valve chamber, whereby the valve is forced by the motive Huid in such space at one end of the valve chamber to the opposite end thereof.

3. The combination ot' a cylinder having ports and passages for the admission and haast of motive fluid. a piston reciproeable therein.y and valve mechanism controlling said admission ports and passages comprising a cage formed of a shell and two valve fluid at each end of the sheil between it and Vthe seats, whereby the valves is forced by the motive fluid in such space at one end of the shell to the opposite end thereof, said shell having openings for the admission of themotive lHuid.` 4, The combination of' a 'cylinder having portsv and passages for the admission and exhaust of-motive iluid, a plston reciprocable in the cylinder, and valve mechanism controlling said admission ports and passages comprising a cage formed inthree separable sections consisting of two valve-seats and a shell, a valve therein, said cylinder having a valve chamber to'receive the cage, and yielding means for holding said sections together and theentire valve cage in 'position within. the valve chamber.

v5. The combination `of a1 cylinder` having ports and passagesfor the admiSsio/nand exhast'ofjmotive fluid, a piston reciprocable in lthe ,cylindeigfand valve mechanism controlling saidfadn ii ssion ports and passages y comprisingacageformed'inthree separable sections consisting. o'pfzztwo valve seats `and a.

shell, a valve therein, said'cylinder having a v valve chamber to receive the cage, and a l spring for holding the valve cage in position within the'fva'lve chambezi.

' ,6. The combination of a cylinder having ports and passagesfor the admission and exhaust of motive fluid, a piston reeiprocable in the cylinder., and valve 'mechanism con- 'rolling said admission ports-and passages w comprising a cage formed inthree separable sections consisting of-'two valveseats and a shell, a valve t'hereii'i,v- ,said cylinder having a valve chamberl'to receive the cage, and. aV

spring bearing di'rectly'against one of the valve seats forholding the valvecage in povsition Within the valve chamber. Y

sections consisting of' two valve seats and a spring arranged within snch chamber between said cap'and valve cage.

8. The ,combination of a cylinder having v ports and passages .for the admission and exhaust ofmotive fluld, apiston reciprocable in the cylinder, and valve .mechanism controlling said admission ports and passages comprising a, cage formed in three separable sections consisting of two valve seats'anda shell, a valve therein, said cylinder having a valve chamber toreceive the cage, a cap closing an end of thevalve chamber and having a sliding fit therein, and the valve cage also havingaJ s liding but air-tight fit withinthe chamber and Vlocated at the other end thereof, and means for holding the valve cage in position. f j

9. The combination of a `cylinder having ports and passages for the admission and exhaust of motive fluid, a pistonireciprocable in the'cylinder, and valve mecchanism controlling said p admission portsand `passages comprising a cage formed oftwo' valve seats and a shell, avalve therein', said cylinder having a valve chamber to receive" the cage, a cap closing an end ofthe valvechamber and having a sliding. fit therein, and the valve cage also having a Sliding but air-:tight fit within the. chamber and located atthe other end thereof, and

thaust of motiveluid, a 'piston reciprocable in the cylinder, and 'valvemechanism controlling said admision ports and ps assagefA comprising a cage formed of two valve seats 4and a shell,a valve4 therein,said-cylinder having a valve chamber to receivethe cage, a cap closing an end ofthe valve chamber and having la sliding fit therein, a valve cage within the chamber, a sprin between the cap andl cage, and a handle c amped t0 the cylindfer and bearing againstthe cap to hold i it in place.

l MATHER viLjsHERWoon.A

Witnesses:

SAMpEL E. Human RoBn'r Dominicanar 

